Computer networks have been in existence since the 1950's. Wide area networks were created in 1965 while local networks such as ethernet began in the mid 60's. Ethernet continues to be the major layer 1 and 2 protocols. The physical layer has changed from coaxial cable to thick ethernet and then onto a variety of cabling such as ethernet over power lines and on optical fibre.
Ethernet continues to be a major layer 1 and 2 protocol imply because much of the internet uses it, and a large part of IoT systems are just built on the internet.
However, there are a range of other wired technologies which were designed for low signaling rates, often for connecting sensors and actuators. These include 1-wire, 2-wire, I2C, X10 and LonTalk. These still find their use in IoT systems.
In the wireless space, the two most common systems are WiFi and Bluetooth. These are heavily deployed in powered situations or where battery recharging is easy, such as with mobile hpones and laptops.
However, they are both heavy consumers (relatively) for devices which may need to be left unattended for long periods with no power regeneration capability. The actual consumption of these is a complex issue: some power is used to maintain a connection; more is used during transmission and reception of data; less is used during sleep mode. In addition, IEEE 802.15.11a/g uses less power than IEEE 802.15.11b. Nevertheless, if you are looking at wireless communications using common batteries, a life of a few days to a few weeks should be all you expect.
Lower power protocols have been developed. The two major ones for PAN (personal area networking) are based on IEEE 802.15.4 and Bluetooth LE (low energy).
IEEE 802.15.4 covers the physical and media access layers (ISO layers 1 and 2). Higher layers are covered by protocols such as 6LoWPAN, ZigBee, Z-Wave and Thread. Of these, only 6LoWPAN is an open specification.
Bluetooth LE is not compatable to Bluetooth at the lower layers, but covers the same ISO stack: from the physical layer right through to the application layer. Bluetooth LE is managed by the Bluetooth SIG, which licenses the patents.
There are also a number of long range protocols such as LoRaWAN, SigFox and NB-IoT. These have a range of about 15-30 kilometres. See for example LoRa Network Protocol and Long Range Wireless IoT
Copyright © Jan Newmarch, firstname.lastname@example.org
"The Internet of Things - a techie's viewpoint" by Jan Newmarch is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Based on a work at https://jan.newmarch.name/IoT/.
If you like this book, please donate using PayPal